Dear list, Someone on paddlewise had some questions about regelcoating a hull and what grits to use. I took the liberty to exclude their private e-mail and send the answer via the list. If the subject matter does not interest you, just delete now. Thanks. Doug Lloyd I woodwork and do my own fiberglass repair work. In both cases, I always buy German quality sandpaper. Someone mentioned this on a previous post I recall, with respect to the random sander and quality paper. But it is true for the hand sanding applications too. If you do get the quality paper (I usually shop at automotive body-shop supply depots, it is gold or dark rust in color, as opposed to tan, brown or white), you can go a bit lighter in grit, thereby eliminating the deep scratch pattern of a courser grit. Because you are using a quality paper, the grit won't wear out too quickly like it would with the cheaper paper. The biggest problem with hull preparation is filling all the imperfections with the filler of your choice: if you put too much on, and we all do, you need a bit coarser grit and a lot of elbow grease. I gave up on the small scratches with normal fiberglass fillers, and started using a German creamy auto-body filler (for smaller dings/scratches only). BTW, the reason you don't want to sand the hull severely with a power sander is because that hull came out of a perfect mould. The second you start to remove material, it will be totally uneven ever after, whereas filled negative depressions back to level and then encasing the hull in an even coat of gelcoat or paint restores a factory look and feel (with a bit of extra weight). I usually give the whole hull a sand-down with 150, then 220, then 320 or 340. You don't want it too smooth, or the new gel coat will not adhere. Technically, they recommend 100 to 150 grit only, to allow the "bite" necessary. I find that a bit too coarse. As far as repair work, it is very difficult to get patch work to stay in place, even after the new gelcoat top-coats the whole hull and repaired area, if you drag your boat over a log or something. This is why I went to epoxy repair material - but then the gelcoat, which is polyester based, will not stick to epoxy repair work, necessitating that I go to epoxy paint. Gelcoat is a better choice in some regards, but with the spray painted epoxy paint, it comes out finished shiny, no sanding/buffing required. Also, you need to understand well that gelcoat applied to an existing hull is very thin stuff indeed, nothing like the original. In fact, it is like thick paint. Of course, you can put on multiple thin coats of gelcoat to get some decent protection. To my way of thinking, though, the reason for regelcoating over the old gelcoat is one of restoring the looks of the kayak and providing a homogeneous look after minor repair and fill work. Finishing new gelcoat depends on how well applied it was and what level of finish you want. I would go with 280, 340, then on to wet and dry at that point (the dark gray paper that you use with water). I have grits up to 2000 I use for solid surface counter top work. Buffing and buffing compounds can all be had from an automotive store or some items rented. Please let me know if there are any other questions. I teach kayak repair workshops for my club. DL *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************
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